A brake complaint is a symptom with a short list of suspects — the pedal feel and the timing narrow it fast.
Customers describe brakes by feel: soft, hard, pulling, shaking, noisy. Each of those points at a small group of causes, and one discriminating test usually separates them. Work the symptom, not a guess — and remember the hydraulic rules from Module 00: spongy is air, a sinking pedal with no leak is the master cylinder.
⚑ Pulsation isn't "warped rotors" by reflex
A pulsating pedal is almost always rotor thickness variation or excessive lateral runout — measurable with a micrometer and dial indicator — not a vague "warp." Measure it, because the fix (machine vs replace, and correcting runout) depends on the numbers.
02 The Complaint Board
Tap the customer's complaint. Get the likely causes and the one test that nails it.
03 What If…
Reason first, then reveal.
?The pedal is hard and stopping takes heavy effort. You shut the engine off, pump the pedal a few times, then start it — the pedal drops. What does that tell you?
The booster and vacuum supply are working — pedal drop on start-up means vacuum assist is present. So a hard pedal with a good drop points elsewhere (seized caliper, glazed linings). If the pedal didn't drop, suspect the vacuum booster, hose, or check valve.
?The car pulls right only when braking, and the right front wheel is hot after a drive. Cause?
A dragging right-front brake — a sticking caliper slide/piston or a collapsed flex hose acting as a one-way valve, holding pressure on that wheel. The heat confirms it. (A steady pull that's there without braking is alignment — see the A4 track.)
?A squeal that stops when the brakes are applied, then returns when released. What is it?
The wear-indicator tab — a spring clip designed to squeal against the rotor at low pad thickness and go quiet under pressure. It's telling you the pads are near their limit. Measure and replace. A grind, by contrast, is metal-to-metal — already too late.
04 Practice
ASE-style. Pick an answer to see why.
05 Recap
Spongy/low pedal = air or fluid loss — bleed, check level and for leaks.
Hard pedal = lost power assist — test the vacuum booster (pedal should drop on start-up).
Pull when braking = a dragging caliper or collapsed hose on one side (hot wheel).